Printing device with interchangeable printing members

ABSTRACT

A printing device comprising a continuously rotating disc having a plurality of flexible type carrying segments and a hammer for causing individual segments to move into contact with a paper on a platen. Control means are provided for actuating the hammer at the proper instant relative to the constantly rotating disc so that the preselected character is printed.

United States Patent Becchi Mar. 28, 1972 541 PRINTING DEVICE WITH3,289,805 12/1966 Kleinschmidt et al. ....197/53 x INTERCHANGEABLEPRINTING 3,309,989 3/ 1967 Solheim et al. ..101/93 BE S 3,313,389 4/1967Cralle, Jr ..197/90 X 3,321,768 5/1967 Byrd .101/93 UX Inventor:Raffaele Becchi, lvrea, Italy 3,332,068 7/1967 McLaughlin et al...101/93 x 73 A 1 CI n C & C. s A. T Cunningwell 1 mgm ,3, v p 3,353,41811/1967 OkCUOglO ....74/125.5 3,353,647 11/1967 Hugel ..197/18 Flledi J1969 3,356,199 12/1967 Robinson.. ..197/53 X 3 371 766 3/1968 Staller..197/53 1. N 793,810 1 App 3,442,365 5/1969 Ragland et al... ..197/53 73,461,235 8/1969 Willcox et al.... 101/93 X 1 Foreign ApplicationPriority Data 3,498,439 3/1970 W1llcox ..197/18 Feb. 29, 1968 Italy..50314-A/68 Primary Exammer-Wilham B. Penn 521 vs. C]. ..197/54, 101/93c, 197/18, 14mm"! Examinerclifford Cmwder 97 9 9 Attorney-Birch,Swindler, McKie & Beckett [51] Int. Cl. ..B41j l/26, B41j1/34 [58] Fieldof Search ..197/18, 53, 54, 56-59, ABSTRACT 197/90 82; 101/93; 74/1255 11 13 A printing device comprising a continuously rotating disc having aplurality of flexible type carrying segments and a [56] References Citedhammer for causing individual segments to move into contact UNITEDSTATES PATENTS with a paper on a platen. Control means are provided foractuating the hammer at the proper instant relative to the constantlyrotating disc so that the preselected character is 547,146 10/1895 Hiett..197/54 primed, 2,236,663 4/1941 Adams ....197/53 3,232,404 2/1966Jones, Jr. ..101/93 X 4 Claims, 4 Drawing Figures PATENTEU MAR 2 8 I972SHEET 1 OF 2 INVENTOR. RAFFAELE 8 EC CHI P'ATENTED MAR 28 1972 SHEET 2[IF 2 INVENTOR. RAFFAEL E B ECCHI PRINTING DEVICE WITH INTERCI-IANGEABLEPRINTING MEMBERS CROSS REFERENCES TO RELATED APPLICATION Applicantclaims priority from corresponding Italian Patent application Ser. No.50314-A/68 filed Jan. 29, 1968.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to a high-speed serial printing device fortypewriters, teleprinters, calculators, accounting machines and similaroffice machines, including a disc of elastically flexible material inconstant rotation and having one or more series of types distributedaround one or more respective circumferential zones, the disc beingsubdivided into equal sectors each of which carries a type for the oreach of the said zones. A hammer is adapted to be actuated under thecontrol of an input code to effect the rapid printing of the charactersof said disc when the disc has been correctly positioned.

2. Description of the Prior Art Printing devices of this kind are knownin which the type disc is unremovable and therefore permits only asingle kind of printing corresponding to the series of types carried byit. The art of printing for office purposes, however, often requires theuse of kinds of printing types which differ according to thecharacteristics of the printing sheet, for which reason it is necessaryto have available a plurality of machines of the kind described or it isnecessary to resort to machines of a different kind. Moreover, in thecase where the printing device is fed by machines which operate withdifferent codes, it will always be necessary to interpose a codeconverter between the feeding machine and the printing device, whichoperates with its own fixed code, and this makes the use of the printingdevice complicated and costly.

SUMMARY OF THE INVENTION The object of the invention is to avoid thesedrawbacks and to provide a serial printing device which is adapted tooperate at high speed with the maximum simplicity and reliability ofoperation.

According to the present invention there is provided a printing devicecomprising a flat or dished type disc mounted on a support, and papersupport means, the disc support or the paper support means being movableto provide for serial printing from the disc along a line on the paper,the disc being of elastically flexible material slotted to provide aplurality of equal sectors, each of which carries one or more types inone or more corresponding circumferential zones of the disc, the devicefurther comprising a hammer for striking a selected sector to effectprinting, means for rotating the disc continuously, and means forproviding signals indicative of the angular position of the disc forcomparison with input code signals to determine the instant of operationof the hammer, the disc being mounted removably on the disc support andinterchangeably with other type discs.

Moreover, in the known printing devices of the kind described there is acertain friction between the sector-like tongue or strips of the discand the striking hammer if the arrangement is not properly timed andwell adjusted so that the time for the striking of said hammer on atongue and the rebound of the hammer is less than the time taken by thetype disc to perform a rotation equal to the angle occupied by asector-like tongue. In order to avoid fouling or obstruction between thehammer and the tongues of the disc, with resultant damage to the tonguesthemselves it is further proposed that the hammer has a head which isarticulated and held in the position suitable for rapid printing bymeans of a return spring.

Another disadvantage of the known printing devices of the kind describedis that the movement of a type whose tongue has been rapidly struck bythe hammer is oblique with respect to the printing plane, inasmuch as itis the result of the compounding of two movements, that is the constantrotation of the disc and the movement perpendicular to the disc itselfowing to the effect of the bending of the tongue. Therefore, since eachtype carried by a tongue does not have a movement exclusivelyperpendicular to the printing plane, it drags partially on the latterwith detriment to the distinctness of the impressed characters. In orderto obviate this drawback the sectors can also be flexible in thecircumferential direction, so that at the instant of impact with theprinting sheet each type tongue can be checked so as to render thedragging with respect to the printing sheet very slight and thus avoidsmudging of the print.

Finally, in a known printing device of the kind described in which saiddisc is carried by a transversely movable carriage, step-by-step advanceof the carriage is effected by a screw set in motion by the continuousrotation of a motor by means of a friction clutch and arrested in thesuccessive printing positions by means of a ratchet gear controlled byan electromagnet, the control of this electromagnet being effected bymeans of a special control device. This device, however, still has thedisadvantage of requiring two separate devices for controlling thestriking of the selected type and for the movement of advance. Thisdisadvantage can be obviated in that signals generated by the rotationof the type disc control the electromagnet.

BRIEF DESCRIPTION OF THE DRAWINGS:

The invention will be described in more detail, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a perspective view of one embodiment of a printing deviceaccording to the invention;

FIG. 2 is a front view of the type disc and associated parts included inthe printing device of FIG. 1;

FIG. 3 is a cross-sectional view taken along line IIl--III of FIG. 2;and

FIG. 4 is a perspective view of a second embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS:

Referring to FIG. 1, the printing device includes a printing roller orplaten 1, on which there lies a printing sheet 2, and also a carriage 3movable transversely of the printing sheet along a guide 4.

The carriage 3 runs on the guide 4 by means of rollers 5 mounted on ballbearings and is drawn along by a screw 6 engaging with a nut screw 34fast with the carriage. Mounted on the carriage is a pulley 7 rotatableon a spindle 8 and rotated by friction by a belt 9 running on a drivingpulley 10, an idler pulley 11 and two opposing rollers l2, 13 whichserve to keep the belt 9 under tension and frictionally engaged with thepulley 7 over a circumferential arc. The driving pulley 10 is constantlyrotated by an electric motor not shown in the drawing. A type disc 14 ismounted fast and coaxial with the pulley 7, on spindle 8, and is lockedthereto by means of a resilient stirrup or circlip 16 engaging in agroove 15.

The disc 14 (FIGS. 1 and 2) is made of elastically flexible material(for example steel) and has its peripheral rim portion subdivided intosector-like tongues or strips 17 which are alike and separated by radialslots 18 of constant width. A segment 19 of the peripheral rim portionis without said tongues 17 and its width is chosen so as to obtain acertain optical result, as will be made clear hereinafter.

Each tongue 17 carries a printing type 32 (FIGS. 2 and 3) belonging to aseries or set of types distributed around a circumferential zone of thedisc 14. [fit is desired to have a larger number of printing typesavailable, each tongue may carry a second printing type 33 belonging toa second series or set of types distributed around a secondcircumferential zone of the disc 14. In this second case, the disc mustbe connected to a suitable positioning system 64 indicateddiagrammatically in FIGS. 2 and 3, which is adapted to shift the disc 14perpendicularly to the writing line for choosing a printing typebelonging to one or the other series available on the disc 14.

Pivoted on a pin 21 fixed to the carriage 3 is a hammer normally bearingagainst a stop pin 23 owing to the action of a return spring 22 anchoredto the carriage. The arm of the hammer 20 has a certain elasticflexibility. The stop pin 23 is carried by a bail 24 which is alsofulcrumed on the pin 21. The bail 24 is normally held so that it bearsagainst a stop (not shown in FIG. 1) fast with the carriage 3 owing tothe effect of a return spring 25 anchored to the carriage. Fixed to thebail 24 is the armature 26 of an electromagnet 27 supported by thecarriage 3 and controlled in the manner which will be describedhereinafter.

The operative end 28 of the hammer 20 carries an articulated head 29mounted on a pin 30 and held in the normal state by a return spring 31anchored to the arm of the hammer 20.

When the electromagnet 27 attractsthe armature 26, the bail 24 pivots onthe pin 21 and acts on the hammer 20 by means of the pin 23, carryingthe hammer along in rapid rotation about the pin 21 until the rod 20strikes against a stop element 62, after which the end 28 of the hammercontinues its movement owing to the effect of the elastic bending of therod 20 and the hammer goes on to strike a tongue 17 of the type disc 14.Under the effect of the blow of the hammer, the tongue 17 bends withrespect to the disc 14 and strikes the printing sheet 2 arranged on theplaten 1, imprinting the character thereon. A suitable ribbon inkingsystem not shown in the drawing co-operates in the printing of thecharacters on the sheet 2.

The sectors of the type disc are also flexible in the plane of the discitself, i.e. in the circumferential direction, so that each tongue 17,which after being struck by the hammer 20 has an oblique movement withrespect to the printing sheet 2 due to the effect of the compounding ofthe rotary and bending movements, can be checked or braked in itsperipheral speed of rotation at the instant of impact of the type withthe printing sheet in such manner as to render the dragging of theprinting type with respect to the sheet very slight.

The articulated head 29 of the hammer 20 avoids fouling occurring in thecourse of the printing operation between the tongues 17 of theconstantly rotating type disc and the hammer itself when the striking ofthe hammer is not properly timed and the time for the striking of saidhammer on the tongue and the rebound of the hammer is not well adjustedso as to be within and less than the time taken by the type disc toperform a rotation equal to the angle occupied by a tongue 17. Thearticulation of the head 29 prevents damage to the tongues of the disc14 and intervenes in the cases of malfunction which have just beenmentioned by means of the rotation of the head 29 under the action ofimpact with the side of a tongue and reduces the effect to a mererubbing of the head 29 on the tongue following the strike by the hammer.

As has already been said, the transverse advance of the carriage 3 takesplace by means of the system consisting of the screw 6 and the nut screw34. The advance is of the step-bystep type, each step being equal to thedistance between two successive columns of writing, and is controlled bya system comprising a ratchet wheel 35 fast with the screw 6 andcontrolled by a pawl 36, a driven gear wheel 37 coaxial with the ratchetwheel 35 and connected to it by friction under the action of a pressurespring 38, and a driving gear wheel 39 meshing with the driven gear 37and rotated continuously by an electric motor not shown in the drawing.This motor may be the same motor that produces the rotation of thepulley 10.

The pawl 36 is pivoted on a pin 40 and is held in the normal positionfor locking the ratchet wheel 35 by the action of a spring 41 connectedto a fixed point of the frame of the machine. The pawl 36 carries anarmature 42 which can be attracted by an electromagnet 43 fixed to theframe of the machine when it is energized in the manner describedhereinafter.

When the annature 42 is attracted, the ratchet wheel 35 can coupleitself freely to the gear 37 by friction and the screw 6 is thereforecaused to rotate, thus producing an advance of the nut screw 34 and ofthe carriage 3 fast with it. So that the advance may take place bysuccessive steps corresponding to the successive columns of writing, therotation of the ratchet wheel 35 by an angle equal to a tooth is such asto permit the transverse advance of the carriage 3 by acolumn ofwriting, for which reason the armature 42 must be controlled by theelectromagnet 43 so that the pawl 36 releases the ratchet wheel 35 onlyfor the time necessary for a rotation equal to one tooth; that is, thepawl 36, by disengaging itself from one tooth, will release the ratchetwheel 36, thereafter to lock it by immediately engaging the followingtooth.

A return spring not shown in the drawing enables the carriage 3 to bereturned to the starting position at the end of each line of writing orwhen a command for return to the beginning is supplied.

The system enabling the position of the type disc 14 to be controlled soas to obtain the printing of the selected character will now be brieflydescribed.

The selection of the type for printing can be effected by means of aknown optical system which employs a light source and photosensitivemeans which co-operate with a timing disc; the latter has a referencenotch and a series of notches each corresponding to a different angularposition of the types. The data received as input, for example from akeyboard, from a perforated tape or a magnetic recording tape, from thestore of a computer, actuate the printing hammer when a given type is inthe printing position.

More particularly, in this embodiment of the invention, the type disc 14is used as the timing disc and as notches there are employed the radialslots 18 which separate the sector-like tongues 17. The reference notchis constituted by the sector 19 without any tongues, which has a radialdepth greater than the ring of tongues 17, as can be seen from FIGS. 1,2and 3. A light source 44 sends a light beam which is picked up throughthe apertures in the disc 14 by two photoelectric cells 45, 46. Thephotoelectric cell 45 picks up the light beam transmitted by the source44 through the slots 18 and the aperture 19, while the photoelectriccell 46 receives only the light beam transmitted through the aperture19.

The photoelectric cell 45 is connected to a counter 50 which advances byone step at each light pulse received by the photoelectric cell 45through the apertures in the disc 14. The counter 50 counts cyclicallyin synchronism with the rotation of the disc 14, in other words itadvances by one step at each rotation of the disc 14 equal to the angleof a sector 17 and returns to the initial configuration after a completerevolution of said disc, so that to each configuration of the counterthere corresponds a well-def'med type on the disc 14. The zero posi tionof the disc 14, and correspondingly of the counter 50, is identified bythe passage of the aperture 19 in front of the light source 44. In thiscondition, in order to obtain reliable zeroizing of the counter 50, thephotoelectric cell 46 is also energized (as explained hereinbefore) andcauses a zeroizing pulse to be transmitted to the counter 50. Moreover,the counter 50 operates so that each configuration assumed by itrepresents the type carried by the tongue 17 which is currently in theposition suitable for printing, that is in correspondence with the head29 of the hammer 20. A suitable comparison device 52 provides forcomparing the representation in code of the character to be printedsupplied at the input with the configuration of the computer 50,producing in the case of coincidence a pulse which energizes theelectromagnet 27 and thereby causing the action of the hammer 20 on thedisc 14 in correspondence with the character to be printed. The lightpulse produced at the photoelectric cell 46 by the passage of theaperture 19 in front of the source .44 also causes the energization ofthe electromagnet 43 and, therefore, the raising of the pawl 36 for atime sufficient for the ratchet wheel 35 to perform a rotation equal toone tooth, so that the carriage 3 advances by one printing step in themanner which has been described hereinbefore.

This printing device according to the invention can therefore operatecontinuously, printing a character for each revolution of the type discand advancing by one printing step at the end of each revolution of thedisc. It is clear that the device described will permit printing only ifthere is present a character supplied as input to the device and thetransverse advance of the carriage can be arranged to occur only whenthere is a following character to be printed.

It will be observed that the electromagnet 43 is controlled by pulsesgenerated by the rotation of the type disc 14, which therefore alsoperforms the function of command of the transverse advance. It willmoreover be observed that the aperture 19 in the disc 14 also performsanother function, inasmuch as by stroboscopic effect it produces for theobserver the persistence of an optical window or gate in correspondencewith the head 29 of the hammer, thus permitting immediate reading of thecharacters printed.

FIG. 4 shows a modified embodiment of the printing device according tothe invention. The purpose of this second constructional form is toincrease the strength of the tongues 17 of the type-bearing element,reduce the peripheral speed of the types carried by the element andpermit easier selection of the various series of types distributed overdifferent circumferential zones.

To this end, the type-bearing disc is strongly dished to the form of abell 47 the lateral surface of which is subdivided into tongues 48disposed generally parallel to the axis of the disc and separated byslots 49. Two or more series of types 50, 51 may be disposed ondifferent circumferential zones, so that each tongue 48 carries a typeof each series. This bell shape of the type-bearing element makes itpossible to obtain, for an equal number and given peripheral width ofthe tongue sectors, tongues which are less tapered and with a wider zoneof attachment 52 than in the embodiment with the plane disc which isshown in FIGS. 1 and 2; this structure therefore becomes more robust asa whole. Moreover, with the bell shape of the type-bearing element, foran equal number and peripheral width of the tongue sectors and for anequal speed of rotation of the type-bearing element, the peripheralspeed of the types becomes lower and, therefore, the dragging of thetypes on the printing sheet which is the cause of blurring of the printis further reduced.

Finally, with the bell shape of the type-bearing element, it is possibleto obtain easy positioning of said element in correspondence with theselection of the types of one or the other series, as describedhereinafter.

The bell 47 is mounted removably on a shaft 54 which has a pulley 55keyed thereto. The shaft 54 is slidable in but rotates as one with thepulley 55 owing to the effect of a key 56 engaging in a groove 60. Thepulley 55 lies in a fixed plane and is set in motion by a belt 57 whichis kept tensioned against an arc of the pulley by two opposing rollers58 and 59.

The shaft 54 can thus slide axially under the action of a positioningelectromagnet 61 which permits the selection of the types of the series50 or the series 51. The notch of a sector 53 of the bell 47 enables thesame stroboscopic effects to be obtained as with the aperture 19 in thedisc of FIG. 1 for observation of the characters printed.

Fig. 4 does not show the other conventional parts forming part of theprinting device for reasons of simplicity and clarity and because theycan easily be adapted from the embodiment illustrated in FIG. 1.

It is to be noted that in both the embodiments illustrated in FIGS. 1and 4 the type-bearing disc is mounted removably on the carriage and cantherefore be exchanged for other typebearing discs so as to permitdifferent kinds of printing. Moreover, an important advantage of theinvention is that the interchangeable type-bearing elements make itpossible for the printing device to operate when the feed is effected bymeans of difi'erent input codes, inasmuch as it will be sufficient tochoose the distribution of the types on the tongues of the carryingmember in such manner that it is in relation to the selected input code.In other words, since there corresponds defined type on the type-bearingelement, to beprecise that which is in the position suitable for beingstruck at the instant of the configuration, and as the sameconfiguration of the counter represents different types according to thecode to which reference is made, in order to obtain a type-bearingelement which can function with a given code it will be sufficient todistribute the types thereon in such manner that, once the element hasbeen mounted on the printing device, there corresponds to eachconfiguration assumed by the counter during the rotation of thetype-bearing element, in the striking position, that type which isrepresented by the said configuration in the code selected.

Although only a single type disc has been described in relation to eachembodiment, it is clear therefore, that a series of interchangeablediscs will be provided. In general such discs will all carry somecorresponding types, as well as types individual to certain discs only,and on some discs types will be positioned differently from thecorresponding types on other discs in accordance with different inputcodes with which the discs are intended for use.

Various modifications of, and alternatives to, the embodiments describedare naturally possible. For example, the arrangement of the printingsheet with respect to the type-bearing element and the hammer may bechanged and the step-bystep transverse advance system may be modified bykeeping the type-bearing element in a fixed position and translating theplaten with the relevant printing sheet instead.

1. I claim:

l. A printing system adapted for printing characters of any particularlanguage in response to coded input information from a selected one of aplurality of input units wherein said input units utilize differentcoded signals to represent the same character to be printed, comprising:

rotatable disc support means for carrying a single mounted disc;

a character carrying disc dished to the form of a bell removably mountedon said rotatable support, said disc adapted to carry characterscorresponding to input information from one of said plurality of inputunits, said disc comprising elastically flexible material and includinga plurality of equal sectors, each of the sectors of the disc beingsubstantially L-shaped, each of said sectors carrying one of saidcharacters disposed in a circumferential zone of the disc, saidcharacters being located on the outer surface of the bell adjacent thediscs circumferential periphery,

paper support means disposed adjacent to said mounted disc and saidrotatable disc support means, said support means being movable relativeto said paper support means to provide for serial printing from the discalong a line on a paper supported by said support means;

an actuable hammer adjacent said mounted disc when the sector is at agiven angular position, the hammer striking the inner surface of thedisc;

means for rotating said mounted disc to move each of said plurality ofsectors of the disc seriatim through said given angular position; and,

control means for providing a coded indication of the particularcircumferentially located sector which is passing through said givenangular position, said control means including a reference point on saiddisc and means for detecting said reference point, said coded indicationbeing compared with said coded input information from said selected oneof said input units so that correspondence between said indication andsaid information causes said hammer to be activated to print one of saidcharacters, the character being printed being determined by the discmounted on said support.

2. A printing system adapted for printing characters of any particularlanguage in response to coded input information from a selected one of aplurality of input units wherein said input units utilize differentcoded signals to represent the same to each configuration of the countermentioned before a wellcharacter to be printed, comprising:

rotatable disc support means for carrying a single mounted disc;

a character carrying disc removably mounted on said rotatable support,said disc adapted to carry characters corresponding to input informationfrom one of said plurality of input units, said disc comprisingelastically flexible material and including a plurality of equalsectors, each of said sectors carrying one of said characters disposedin a circumferential zone of the disc,

paper support means disposed adjacent to said mounted disc and saidrotatable disc support means, said support means being movable relativeto said paper support means to provide for serial printing from the discalong a line on a paper supported by said support means;

an actuable hammer adjacent said mounted disc for striking a sector ofsaid plurality of sectors of said mounted disc when the sector is at agiven angular position, said hammer including an arm, an articulatedhead mounted on said arm substantially perpendicular thereto, andrelease means for releasing said head from a rigid position, said meansfor releasing being adapted to cooperate with the edges of said sectorsto be activated when the head of said hammer, striking between adjacentsectors, strikes the edge of one of said adjacent sectors, said meansfor releasing being inoperative when said hammer head strikes a singlesector, said means for releasing including a return spring connectingsaid head and said arm for biasing said head to an unreleased position;

means for rotating said mounted disc to move each of said plurality ofsectors of the disc seriatim through said given angular position; and,

control means for providing a coded indication of the particularcircumferentially located sector which is passing through said givenangular position, said control means including a reference point on saiddisc and means for detecting said reference point, said coded indicationbeing compared with said coded input information from said selected oneof said input units so that correspondence between said indication andsaid information causes said hammer to be activated to print one of saidcharacters, the character being printed being determined by the discmounted on said support.

3. A printing device comprising:

a rotatable disc support mounted on a transversely movable carriage;

a type carrying disc mounted on said rotatable support, said disccomprising elastically flexible material and including a plurality ofequal circumferentially located sectors, each sector carrying a typedisposed in a circumferential zone of the disc, said disc beingremovably mounted on the support and selectively interchangeable withother type discs;

paper support means disposed adjacent said disc, said rotatable discsupport and said support means being relatively movable to provide forserial printing from the disc along a line on a paper supported by saidsupport means;

a hammer adjacent the disc and actuable for striking a sector of saidplurality of sectors of the disc at a given angular position of thedisc;

means for rotating the disc to move each of said plurality of sectorsseriatim through said angular position;

indicating means for providing signals indicative of the sector of saidplurality of sectors occupying said angular position of the disc forcomparison with input code signals to determine the proper instant foroperation of the hammer;

a continuously rotating motor for advancing said carriage step-by-steppast a printing station;

a friction clutch coupling said motor to said carriage;

ratchet means for arresting successive portions of said carriage in saidprinting station;

an electromagnetic device cooperating with said ratchet means andenergizable to permit a one-step movement of said carriage" and,

control means for generating a command signal to energize saidelectromagnet, said control means including a reference gap on said discand a photoelectric means for generating said command signal upondetecting said gap during rotation of said disc.

4. A printing device comprising:

a rotatable disc support;

a type carrying disc mounted on said rotatable support, said disccomprising elastically flexible material and including a plurality ofequal circumferentially located sectors, each sector carrying a typedisposed in a circumferential zone of the disc, each of said sectorsbeing identified by a code signal, said disc being removably mounted onthe support and selectively interchangeable with other type discs;

paper support means disposed adjacent said disc, said rotatable discsupport and said support means being relatively movable to provide forserial printing from the disc along a line on a paper supported by saidsupport means;

a hammer adjacent the disc and actuable for striking a sector of saidplurality of sectors of the disc at a given angular position of thedisc;

means for rotating the disc to move each of said plurality of sectorsseriatim through said angular position;

indicating means including:

a plurality of equal reference slots on said disc, each of said slotsbeing defined by two contiguous sectors of said plurality of sectors,

a reference gap on said disc, said gap being wider than each slot ofsaid plurality of slots,

a photoelectric system including means for generating a counting pulseupon detecting one of said slots and a start command upon detecting saidreference gap during rotation of said disc,

and counter means for representing cyclically the code signalsidentifying the successive sectors of said plurality, said counter beingresponsive to said start command to represent the sector next passingthrough said given angular position after said gap and being furtherresponsive to each counting pulse to represent each of the followingsectors; and

control means for comparing the code signal indicative of the particularsector of said plurality of sectors which is passing through said givenangular position of the disc with an input code signal to determine theproper instant for operation of the hammer.

1. A printing system adapted for printing characters of any particularlanguage in response to coded input information from a selected one of aplurality of input units wherein said input units utilize differentcoded signals to represent the same character to be printed, comprising:rotatable disc support means for carrying a single mounted disc; acharacter carrying disc dished to the form of a bell removably mountedon said rotatable support, said disc adapted to carry characterscorresponding to input information from one of said plurality of inputunits, said disc comprising elastically flexible material and includinga plurality of equal sectors, each of the sectors of the disc beingsubstantially L-shaped, each of said sectors carrying one of saidcharacters disposed in a circumferential zone of the disc, saidcharacters being located on the outer surface of the bell adjacent thedisc''s circumferential periphery, paper support means disposed adjacentto said mounted disc and said rotatable disc support means, said supportmeans being movable relative to said paper support means to provide forserial printing from the disc along a line on a paper supported by saidsupport means; an actuable hammer adjacent said mounted disc when thesector is at a given angular position, the hammer striking the innersurface of the disc; means for rotating said mounted disc to move eachof said plurality of sectors of the disc seriatim through said givenangular position; and, control means for providing a coded indication ofthe particular circumferentially located sector which is passing throughsaid given angular position, said control means including a referencepoint on said disc and means for detecting said reference point, saidcoded indication being compared with said coded input information fromsaid selected one of said input units so that correspondence betweensaid indication and said information causes said hammer to be activatedto print one of said characters, the character being printed beingdetermined by the disc mounted on said support.
 2. A printing systemadapted for printing characters of any particular language in responseto coded input information from a selected one of a plurality of inputunits wherein said input units utilize different coded signals torepresent the same character to be printed, comprising: rotatable discsupport means for carrying a single mounted disc; a character carryingdisc removably mounted on said rotatable support, said disc adapted tocarry characters corresponding to input information from one of saidplurality of input units, said disc comprising elastically flexiblematerial and including a plurality of equal sectors, each of saidsectors carrying one of said characters disposed in a circumferentialzone of the disc, paper support means disposed adjacent to said mounteddisc and said rotatable disc support means, said support means beingmovable relative to said paper support means to provide for serialprinting from the disc along a line on a paper supported by said supportmeans; an actuable hammer adjacent said mounted disc for striking asector of said plurality of sectors of said mounted disc when the sectoris at a given angular position, said hammer including an arm, anarticulated head mounted on said arm substantially perpendicularthereto, and release means for releasing said head from a rigidposition, said means for releasing being adapted to cooperate with theedges of said sectors to be activated when the head of said hammer,striking between adjacent sectors, strikes the edge of one of saidadjacent sectors, said means for releasing being inoperative when saidhammer head strikes a single sector, said means for releasing includinga return spring connecting said head and said arm for biasing said headto an unreleased position; means for rotating said mounted disc to moveeach of said plurality of sectors of the disc seriatim through saidgiven angular position; and, control means for providing a codedindication of the particular circumferentially located sector which ispassing through said given angular position, said control meansincluding a reference point on said disc and means for detecting saidreference point, said coded Indication being compared with said codedinput information from said selected one of said input units so thatcorrespondence between said indication and said information causes saidhammer to be activated to print one of said characters, the characterbeing printed being determined by the disc mounted on said support.
 3. Aprinting device comprising: a rotatable disc support mounted on atransversely movable carriage; a type carrying disc mounted on saidrotatable support, said disc comprising elastically flexible materialand including a plurality of equal circumferentially located sectors,each sector carrying a type disposed in a circumferential zone of thedisc, said disc being removably mounted on the support and selectivelyinterchangeable with other type discs; paper support means disposedadjacent said disc, said rotatable disc support and said support meansbeing relatively movable to provide for serial printing from the discalong a line on a paper supported by said support means; a hammeradjacent the disc and actuable for striking a sector of said pluralityof sectors of the disc at a given angular position of the disc; meansfor rotating the disc to move each of said plurality of sectors seriatimthrough said angular position; indicating means for providing signalsindicative of the sector of said plurality of sectors occupying saidangular position of the disc for comparison with input code signals todetermine the proper instant for operation of the hammer; a continuouslyrotating motor for advancing said carriage step-by-step past a printingstation; a friction clutch coupling said motor to said carriage; ratchetmeans for arresting successive portions of said carriage in saidprinting station; an electromagnetic device cooperating with saidratchet means and energizable to permit a one-step movement of saidcarriage; and, control means for generating a command signal to energizesaid electromagnet, said control means including a reference gap on saiddisc and a photoelectric means for generating said command signal upondetecting said gap during rotation of said disc.
 4. A printing devicecomprising: a rotatable disc support; a type carrying disc mounted onsaid rotatable support, said disc comprising elastically flexiblematerial and including a plurality of equal circumferentially locatedsectors, each sector carrying a type disposed in a circumferential zoneof the disc, each of said sectors being identified by a code signal,said disc being removably mounted on the support and selectivelyinterchangeable with other type discs; paper support means disposedadjacent said disc, said rotatable disc support and said support meansbeing relatively movable to provide for serial printing from the discalong a line on a paper supported by said support means; a hammeradjacent the disc and actuable for striking a sector of said pluralityof sectors of the disc at a given angular position of the disc; meansfor rotating the disc to move each of said plurality of sectors seriatimthrough said angular position; indicating means including: a pluralityof equal reference slots on said disc, each of said slots being definedby two contiguous sectors of said plurality of sectors, a reference gapon said disc, said gap being wider than each slot of said plurality ofslots, a photoelectric system including means for generating a countingpulse upon detecting one of said slots and a start command upondetecting said reference gap during rotation of said disc, and countermeans for representing cyclically the code signals identifying thesuccessive sectors of said plurality, said counter being responsive tosaid start command to represent the sector next passing through saidgiven angular position after said gap and being further responsive toeach counting pulse to represent each of the following sectors; andcontrol means for comparing the code signal indicaTive of the particularsector of said plurality of sectors which is passing through said givenangular position of the disc with an input code signal to determine theproper instant for operation of the hammer.